Average Weather in September in San Mateo del Mar Mexico

Daily high temperatures are around 91°F, rarely falling below 87°F or exceeding 95°F.

Daily low temperatures are around 79°F, rarely falling below 76°F or exceeding 81°F. The lowest daily average low temperature is 79°F on September 12.

For reference, on July 30, the hottest day of the year, temperatures in San Mateo del Mar typically range from 80°F to 93°F, while on January 7, the coldest day of the year, they range from 74°F to 86°F.

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on September. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Clouds

The month of September in San Mateo del Mar experiences gradually decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 92% to 87%. The highest chance of overcast or mostly cloudy conditions is 92% on September 7.

The clearest day of the month is September 30, with clear, mostly clear, or partly cloudy conditions 13% of the time.

For reference, on September 7, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 92%, while on February 20, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 79%.

The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In San Mateo del Mar, the chance of a wet day over the course of September is very rapidly decreasing, starting the month at 50% and ending it at 38%.

For reference, the year's highest daily chance of a wet day is 55% on June 22, and its lowest chance is 1% on January 29.

The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day rainfall during September in San Mateo del Mar is very rapidly decreasing, starting the month at 7.8 inches, when it rarely exceeds 15.4 inches or falls below 2.0 inches, and ending the month at 5.6 inches, when it rarely exceeds 10.5 inches or falls below 1.9 inches.

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.

Sun

Over the course of September in San Mateo del Mar, the length of the day is gradually decreasing. From the start to the end of the month, the length of the day decreases by 26 minutes, implying an average daily decrease of 54 seconds, and weekly decrease of 6 minutes, 16 seconds.

The shortest day of the month is September 30, with 12 hours, 0 minutes of daylight and the longest day is September 1, with 12 hours, 26 minutes of daylight.

The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise of the month in San Mateo del Mar is 7:06 AM on September 1 and the latest sunrise is 2 minutes, 58 seconds later at 7:09 AM on September 30.

The latest sunset is 7:32 PM on September 1 and the earliest sunset is 23 minutes earlier at 7:09 PM on September 30.

Daylight saving time is observed in San Mateo del Mar during 2019, but it neither starts nor ends during September, so the entire month is in daylight saving time.

For reference, on June 21, the longest day of the year, the Sun rises at 6:48 AM and sets 13 hours, 6 minutes later, at 7:54 PM, while on December 22, the shortest day of the year, it rises at 6:43 AM and sets 11 hours, 10 minutes later, at 5:53 PM.

The solar day over the course of September. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray.

Humidity

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

The chance that a given day will be muggy in San Mateo del Mar is essentially constant during September, remaining around 100% throughout.

For reference, on June 1, the muggiest day of the year, there are muggy conditions 100% of the time, while on January 14, the least muggy day of the year, there are muggy conditions 82% of the time.

The percentage of time spent at various humidity comfort levels, categorized by dew point.

Wind

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in San Mateo del Mar is rapidly increasing during September, increasing from 10.8 miles per hour to 13.1 miles per hour over the course of the month.

For reference, on January 1, the windiest day of the year, the daily average wind speed is 19.4 miles per hour, while on June 10, the calmest day of the year, the daily average wind speed is 9.6 miles per hour.

The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Water Temperature

San Mateo del Mar is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average surface water temperature in San Mateo del Mar is essentially constant during September, remaining within 1°F of 85°F throughout.

The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Growing Season

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

Temperatures in San Mateo del Mar are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year.

Time Spent in Various Temperature Bands and the Growing Season in September

The percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within the growing season.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

The average accumulated growing degree days in San Mateo del Mar are very rapidly increasing during September, increasing by 958°F, from 7,841°F to 8,798°F, over the course of the month.

The average growing degree days accumulated over the course of September, with 25th to 75th and 10th to 90th percentile bands.

Solar Energy

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy in San Mateo del Mar is essentially constant during September, remaining within 0.2 kWh of 4.4 kWh throughout.

The lowest average daily incident shortwave solar energy during September is 4.2 kWh on September 7.

The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of San Mateo del Mar are 16.211 deg latitude, -94.982 deg longitude, and 0 ft elevation.

The topography within 2 miles of San Mateo del Mar is essentially flat, with a maximum elevation change of 66 feet and an average elevation above sea level of 13 feet. Within 10 miles is essentially flat (318 feet). Within 50 miles contains only modest variations in elevation (7,119 feet).

The area within 2 miles of San Mateo del Mar is covered by cropland (42%), water (41%), and shrubs (15%), within 10 miles by water (78%) and cropland (18%), and within 50 miles by water (48%) and cropland (29%).

Data Sources

This report illustrates the typical weather in San Mateo del Mar year round, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

Temperature and Dew Point

There are 2 weather stations near enough to contribute to our estimation of the temperature and dew point in San Mateo del Mar.

The estimated value at San Mateo del Mar is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between San Mateo del Mar and a given station.

Other Data

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.